Of course, playing such games on the phone is difficult, there are not enough fingers. The toy is more suitable for PSP where there are many buttons and the screen is larger than iPhone. But the level at which N.O.V.A is made is impressive.
N.O.V.A
First person shooter with complete freedom of movement. An accelerometer can be used as a rotation, this will free up a much needed finger. True, it is better to turn on this mode when there is no one nearby, otherwise your movements will look strange from the side. The task is to follow the arrow and shoot at everything that moves. 
Install from AppStore
N.O.V.A 2
The second part differs from the first not only in the number of screensavers, but also in other graphics. Lighting on wall surfaces, detailing objects, everything at a higher level. Earlier on iPhone this was not. Monsters have become more cunning and intelligent. Management is exactly the same, you don't have to get used to it. There is a possibility of multiplaying via the Internet, wi-fi or bluetooth. All this led to the fact that the size of the toy has grown to 715 megs. 
Install from AppStore